摘要:

The kinetics of polymerization of methyl methacrylate initiated by the redox system Mn3+/crotonic acid was studied in aqueous sulfuric acid in the temperature range of 35-50°C, and the rates of polymerization (Rp), Mn3+disappearance, etc. were measured.

ISSN:0022-233X    

DOI:10.1080/00222338108056794

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Radical copolymerization of styrene (St, M1) with acrylonitrile (AN, M2) has been carried out using azobisisobutylonitrile as an initiator in benzene, dimethylsulfoxide, acetonitrile, and ethanol at 60 and 80°C. Good linear correlationships were obtained by plotting the values of log r1, log r2, Q2, and e2against those ofvC˭N andvC˭C determined in the solvents: the increase in the interaction between AN and the solvent was found to decrease the values of log r1and e2but to increase those of log r2and Q2. The results are discussed in terms of the solvation both in the ground state and in the transition state.

ISSN:0022-233X    

DOI:10.1080/00222338108056795

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Indene (ID) was found to copolymerize spontaneously with polar vinyl monomers containing a nitrile or ester group in the presence of ZnCb and to give rise simultaneously to its cationic homopolymer in the latter comonomer. The formation of a 1:1-charge transfer complex between ID with acrylonitrile coordi-nated to ZnCl2((AN)c) was confirmed by UV-spectroscopic studies and the equilibrium constant for it was estimated to be 0.121 L/mol in AN at 25°C. The overall activation energy for the copolymerization with (AN)c was obtained to be ∼9.8 kcal/mol. An increasing amount of ZnCl2in AN resulted in increases in the copolymerization rate, viscosity, and alternating tendency of the copolymer. The addition of 1, 1-diphenyl-2-picrylhydrazyl to the System ID-(AN)c retarded the copolymerization and induced a cationic polymerization of ID. Further, terpolymers containing ∼50 mol % AN were formed spontaneously in the System ID-styrene-(AN)c. Comparing these results with the corresponding ones obtained for 1,3-cyclodienes as donor monomer reported previously, a discussion is given on the reactivity of ID-(AN)c complex in the initiation and the propagation of the copolymerization. The mechanism of the attendant cationic polymerization of ID is briefly considered.

ISSN:0022-233X    

DOI:10.1080/00222338108056796

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The emulsion polymerization of ethyl methacrylate initiated by the potassium persulfate (I) at 50°C in the presence of an anionic detergent (S), i.e., sodium lauryl sulfate at a low monomer/water ratio, has been ineestigated kinetically by the coneentional dilatometric and graeimetric methods in a phosphate buffer solution of pH 6.85. The number of latex particles per mL of the aqueous phase has been estimated by the soap titration technique, and the aeerage number of latex particles (N) per mL of the aqueous phase has been found to be 1014to 1016, depending upon the experimental conditions. At zero coneersion, the rate of polymerization (Vp) may be written aswhere (I) and (S) denote initiator and soap concentrations, re-spectieely. The eiscosity-aeerage molecular weight (M) of the polymer at 28% coneersion has been found to be

ISSN:0022-233X    

DOI:10.1080/00222338108056797

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The kinetics of polymerization of acrylonitrile initiated by potassium peroxodisulfate in neutral and acid conditions was studied. Rpdepended upon [S2O82-]1/2and [monomer]3/2both in neutral and acid solutions. The influence of ionic strength and the cata-lytic effect of Ag+on the System are discussed. Suitable mech-anisms are proposed.

ISSN:0022-233X    

DOI:10.1080/00222338108056798

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Inverted emulsion, i.e., water-in-oil (W/O) type emulsion, was prepared from styrene solution of unsaturated polyester obtained from Mg salt of mono(hydroxyethyl)phthalate, ethylene glycol (EG), maleic anhydride (MA), phthalic anhydride (PA), and propylene oxide (PO). The inverted emulsion was much more stable than that of blank polyester obtained from EG, MA, PA, and PO, and further than the usual inverted emulsion prepared by treating styrene solution of commercial unsaturated polyester with triethanolamine. By polymerization, the inverted emulsion was transformed to a white solid which was dry to the touch. The water-containing cured resin obtained showed considerably higher physical and other properties than those of commercial unsaturated polyester.

ISSN:0022-233X    

DOI:10.1080/00222338108056799

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The polymerization of isobutylene with VCl4in n-heptane or in the bulk does not proceed in the dark at temperatures lower than -20°C, yet it may be induced by the addition of styrene, α-methylstyrene, p-divinylbenzene, 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene. In these cases the polymerizations proceed with variously long induction periods depending on the type of comonomer used. The shortest induction period was observed after the addition of p-divinylbenzene and 2, 3-dimethyl-1, 3-butadiene. In a nonpolar medium the copolymerization of isobutylene with isoprene or butadiene in the dark gives rise to copolymers insoluble in heptane, benzene, and CCl4, while co-polymers formed with the effect of light are soluble. Unlike polymerizations carried out in a nonpolar solution, the polymerization of isobutylene with VCl4in methyl chloride proceeds spontaneously in the absence of protonic coinitiators. Also, soluble copolymers of isobutylene with isoprene or butadiene arise in the copolymerization in methylchloride solution irrespective of the procedure used when the copolymerization is carried out (in the dark or with the effect of light). Polymerizations and copolymerizations carried out both in nonpolar and in polar solutions are inhibited by the presence of oxygen.

ISSN:0022-233X    

DOI:10.1080/00222338108056800

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The kinetics of the polymerization of ethyl glycidyl ether and allyl glycidyl ether with BF3OEt2as catalyst has been studied. Chain transfer to the monomer has been evidenced. It increased with the monomer concentration and decreased with the increase of the dielectric constant of the solvent used and decreased in the presence of a monomer more basic than glycidyl ethers, for example, 1,3-dioxepane.

ISSN:0022-233X    

DOI:10.1080/00222338108056801

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The polymerization of isobutyl vinyl ether (IBVE) by SK-500 is first order in monomer and directly proportional to the weight of the sieve. Catalytic activity and the solid surface acidity of SK-500 are maximum when the sieve is precalcined at 200°C for 2 h. Pyridine (≈10−4mol/L) inhibits and hydrogen chloride (≈ 10−4mol/L) cocatalyzes the polymerization. Both the rate and molecular weight increase to a maximum at ≈7% uptake of water (g/g of dry sieve) and thereafter fall to a limiting value. Molecular weights increase as the monomer concentration in-creases up to ≈1.0 mol/L and attain a limiting value. Molecular weights increase with precalcination temperature up to 500°C and decline thereafter. Rate increases steadily with temperature over the range 2-60°C while molecular weights increase only up to 30°C, above which a sharp fall is observed. The initiation of the polymerization appears to involve the Bronsted acid sites on the SK-500 molecular sieves through a proton transfer to the monomer molecule and follows a conventional cationic mechanism.

ISSN:0022-233X    

DOI:10.1080/00222338108056802

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The copolymerizations of maleic anhydride (MA) and propylene oxide (PO) were carried out in toluene, dioxane, diethoxyethane, or dimethyldigol solution in the presence of ethylzinc compounds EtZnX (X = Et- or substituted phenoxy group). On the basis of the1H-NMR data of copolymers and VPC of the products of their hydrolysis, it was found that donor solvents and X substituents involving CH3O-, Cl-, or CH3CO- donor groups in the ortho position of the aromatic ring (e.g., X = 2-CH3OC6H4O-, 2,6-(CH3O)2C6H3O-, 2-CH3COC6H4O-, etc.) caused an increase in the number of alternating sequences in copolymers chains. In the reaction of MA and PO in tetrahydrofuran (THF) solution, the above-mentioned zinc compounds gave highly alternating MA-PO-THF terpolymers.

ISSN:0022-233X    

DOI:10.1080/00222338108056803

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor